Conventional fabric softening compositions are added in the rinse cycle of the laundering process to soften fabrics or as dryer added softener sheets to a machine dryer. However, adding such compositions during the rinse cycle can be inconvenient for the consumer, unless the consumer has a laundry washing machine that has a built-in fabric softener dispensing unit, a removable agitator post-mounted fabric softener dispenser, or has a fabric softener dosing device such as the DOWNY® Ball. Otherwise, the consumer has to monitor the laundering process and then manually add the fabric softener to the load as soon as the rinse cycle begins.
Softening-through-the-wash compositions (hereinafter referred to as “STW” compositions) are able to soften fabrics, and provide other conditioning benefits to fabrics while being added to the fabrics in the laundering process during the washing stage, negating the need to add a separate fabric conditioning composition to the rinse stage and/or drying stage of the laundering process. The STW compositions can thus be added to the load of laundry at the beginning of the laundering process, which provides the consumer with an efficient and easy way to soften and freshen fabrics during the laundering process.
It is convenient to provide fabric softening compositions in the form of a unit dose. Previous attempts have been made to provide a unit dose fabric softening composition in the form of a tablet. However, such tablets can tend to leave an undesirable visible residue on the treated fabrics, are suitable only for addition in the rinse cycle, and/or provide only insignificant fabric softening benefits. See, e.g., U.S. Pat. Nos. 6,291,421 and No. 6,110,886. Recent progress has been claimed for STW tablets. See, e.g., WO 04/111167A1. However, there is a growing preference by the consumer for liquid STW products, especially in a unitized dose form.
Thus the need still exists to provide improved softening-through-the-wash compositions that provide effective deposition of a fabric softening active on the treated fabrics to provide the consumer a noticeable softening benefit, while avoiding the deposition of a visible residue on the treated fabrics.